Science - Structure of the Atom
Exam Duration: 45 Mins Total Questions : 30
Which valence shell electron arrangement is that of a metallic element?
- (a)
2,1
- (b)
2,4
- (c)
2,5
- (d)
2,7
An element X has two isotopes, which may be represented as \(\\ ^{ 238 }X\) and \(\\ ^{ 235 }X\). How does \(\\ ^{ 238 }X\)differ from \(\\ ^{ 235 }X\)?
- (a)
\(\\ ^{ 238 }X\)has 3 more protons and 3 more electrons than 235.
- (b)
\(\\ ^{ 238 }X\)has 3 more protons, but same number of electrons as 235
- (c)
\(\\ ^{ 238 }X\)has 3 more neutrons, but the electrons or protons are same as 235
- (d)
\(\\ ^{ 238 }X\)has 3 more protons, but same number of electrons as 235.
An atom of an element contains 17 protons, 18 neutrons and 17 electrons. Which of the following will be the atomic structure of another isotope of this element?
Protons | Neutrons | Electrons | |
(a) | 17 | 20 | 17 |
(b) | 17 | 18 | 16 |
(c) | 18 | 18 | 17 |
(d) | 20 | 18 | 17 |
- (a)
17-20-17
- (b)
17-18-16
- (c)
18-18-17
- (d)
20-18-17
What does an atom and an ion of the isotope of sodium \(_{ 11 }^{ 22 }\) Na both contain?
- (a)
11 electrons
- (b)
12 neutrons
- (c)
23 protons
- (d)
23 neutrons
What is valency?
- (a)
The combining capacity of an element
- (b)
The atomicity of an element
- (c)
The oxidation number of an element
- (d)
All of the above
n element X forms a unipositive ion with the electronic structure 2,8,8. What is the atomic number of X?
- (a)
16
- (b)
17
- (c)
18
- (d)
19
The letters X,Y and Z represent different atoms.
\(\boxed { _{ 19 }^{ 40 }{ X\quad }_{ 19 }^{ 39 }{ Y\quad }_{ 20 }^{ 40 }{ Z } } \)
What can be deduced from the proton numbers and nucleon numbers of X, Y and Z?
- (a)
X and Yare the same elements.
- (b)
X and Z are the same elements
- (c)
X has more protons than Y
- (d)
Z has more neutrons than Y.
What is the maximum number of electrons that can be accommodated in the \({ 4 }^{ th }\) energy level?
- (a)
32
- (b)
18
- (c)
2
- (d)
8
A neutral atom of an element has a nucleus with a nuclear charge 13 times and mass 27 times as that of hydrogen nucleus. What is the ratio of electrons to protons in its stable positively charged ion?
- (a)
27: 13
- (b)
10: 13
- (c)
20:24
- (d)
10: 14
What does Bohr's atomic theory explain?
- (a)
About quantum numbers
- (b)
About the shape of sub-levels
- (c)
About nucleus
- (d)
About stationary states
Which of the following electronic configurations is incorrect?
- (a)
Be (4) = 2,2
- (b)
0 (8)= 2, 6
- (c)
S (16) = 2, 6, 8
- (d)
P (15) = 2, 8, 5
An atom has mass number 23 and atomic number 11. How many protons,electrons and neutrons are present in the atom?
- (a)
11, 12, 13
- (b)
11, 11, 12
- (c)
11,11,13
- (d)
11,14,15
An element has atomic number 17 and mass number 37. There are 17 electrons outside the nucleus. Find the number of neutrons in it.
- (a)
20
- (b)
21
- (c)
17
- (d)
37
What does the mass number of an atom represent?
- (a)
Only the number of protons
- (b)
The number of protons and neutrons
- (c)
The number of protons and electrons
- (d)
Only the number of neutrons
The atom of an element has 10 electrons, 10 protons and 12 neutrons. Find the mass number of the element.
- (a)
10
- (b)
12
- (c)
22
- (d)
32
Which of the following ions is the smallest in size?
- (a)
Mg2+
- (b)
Na+
- (c)
O2-
- (d)
F-
In an element, the number of protons, electrons and neutrons are 1, 0, 1 respectively. Identify the element.
- (a)
D+
- (b)
H+
- (c)
He
- (d)
Li+
Identify the number of electrons present in the outermost shell of atoms of each of the following elements.
(i) Helium (ii) Magnesium (iii) Sulphur |
- (a)
(i) - 2, (ii) - 3, (iii)- 4
- (b)
(i) - 1, (ii) - 4, (iii) - 6
- (c)
(i) - 2, (ii) - 2, (iii) - 6
- (d)
(i) - 3, (ii) - 4, (iii) - 5
The atomic numbers of three elements P, Q and Rare 5,9 and 13 respectively. Which two elements show similar chemical properties?
- (a)
P and Q
- (b)
P and R
- (c)
Q and R
- (d)
P,Q and R
Identify the element having two electrons in the K shell of its atom.
- (a)
Hydrogen
- (b)
He+
- (c)
Helium
- (d)
Deuterium
The total number of electrons in a nitrogen atom and a chlorine atom are 7 and 17 respectively. Find the number of valence electrons in them.
- (a)
3,1
- (b)
5,8
- (c)
4, 1
- (d)
5,7
An element has an atomic number 20. How many electrons will be present in K, L, M and N shells of its atom?
- (a)
2,8,6,4
- (b)
2,8,7,3
- (c)
3,7,7,3
- (d)
2,8,8,2
According to JJ.Thomson's atomic model, where are the negative charges of an atom embedded in?
- (a)
A lump of positive charge
- (b)
A lump of small atoms
- (c)
A lump of neutrons
- (d)
The nucleus
Which ofthe following is a pair of isobars?
- (a)
\(_{ 7 }^{ 15 }{ N }\), \(_{ 8 }^{ 16 }O\)
- (b)
\(_{ 6 }^{ 13 }C\), \(_{ 7 }^{ 14 }N\)
- (c)
\(_{ 6 }^{ 13 }C\), \(_{ 7 }^{ 13 }N\)
- (d)
\(_{ 6 }^{ 13 }C\), \(_{ 8 }^{ 15 }O\)
An isotope of helium is represented by the symbol 32He. How many protons, neutrons and electrons are there in an atom of the isotope?
Protons | Neutrons | Electrons | |
A | 1 | 2 | 1 |
B | 1 | 3 | 2 |
C | 2 | 1 | 2 |
D | 2 | 3 | 2 |
- (a)
1-2-1
- (b)
1-3-2
- (c)
2-1-2
- (d)
2-3-2
Identify the least reactive element from the following.
- (a)
\(_{ 8 }^{ 16 }X\)
- (b)
\(_{ 10 }^{ 20 }X\)
- (c)
\(_{ 11 }^{ 23 }X\)
- (d)
\(_{ 11 }^{ 23 }X\)
What is the ratio of the number of neutrons present in potassium and magnesium atoms with mass numbers 39 and 24 respectively?
- (a)
19: 12
- (b)
5: 3
- (c)
5:6
- (d)
4:3
A beam of alpha-particles is fired at a piece of gold foil as shown below.
After striking the gold foil, in which direction do most of the alpha-particles travel?
- (a)
P
- (b)
Q
- (c)
R
- (d)
S
hich of the following statements about the isotopes of an element is NOT correct?
- (a)
Isotopes have the same proton number
- (b)
Isotopes have the same chemical properties
- (c)
Isotopes have the same nucleon number
- (d)
Atoms of the isotopes of the element have the same number of electrons.
An element X combines with oxygen to form compounds P and Q. If the ratio of the valency of element X in Pto element X in Q is 3 : 5 respectively, what could be
the probable compounds P and Q ?
P | Q | |
(A) | CO | CO2 |
(B) | N2O3 | N2O5 |
(C) | H2O | H2O2 |
(D) | CH4 | C3H5 |
- (a)
CO CO2 - (b)
N2O3 N2O5 - (c)
H2O H2O2 - (d)
CH4 C3H5